Test Detail

Test for the sabino-1 (SB1) allele of the KIT gene, associated with white patches with irregular borders, often on the legs and belly, and with the possible appearance of intermixed white hair. Complementary to, not a substitute for, clinical examination.

Applicable breeds: American Paint Horse, Appaloosa, Haflinger, Lipizzan, Noriker, Quarter Horse and others. Frequencies: limited data.

• White patches with irregular borders on the legs, belly and face.\n• Scattered, intermixed white hair on the body.\n• SB1/SB1 homozygotes show complete or almost complete white.

The sabino pattern was classically described for its dominant inheritance; in 2005 Brooks and Bailey identified a splicing variant in KIT (SB1) associated with the pattern, with homozygotes being almost completely white.

• Avoid SB1 × SB1 if an almost white foal is not sought.\n• The addition of SB1 to other white alleles (tobiano, splashed white, W) increases depigmentation and the risk of deafness.\n• Interpret the pattern together with the other spotting loci.\n• A negative result does not rule out other patterns.

The SB1 allele may not be expressed as a typical pattern in some breeds (carriers without the classic sabino phenotype have been described); this does not invalidate the test, but it must be interpreted alongside the phenotype.

1. Brooks 2005, Exon skipping in the KIT gene causes a Sabino spotting pattern in horses (PMID 16284805); OMIA:000209-9796.
2. Druml 2018, Novel insights into Sabino1 and splashed white coat color patterns in horses (PMID 29635692); OMIA:000209-9796.